Crude oil produced at a marine oil well is carried to a marine structure by using a pipeline which is a kind of a marine structure. The marine structure includes a floating production storage and offloading (FPSO), a tension-leg platform (TLP), a semi-submersible (SPAR), a fixe platform or the like.
At this time, the pipeline is installed in a deep sea as much as several kilometers to several hundred kilometers for the purpose of over 20-year operations.
In this case, the pipeline installed in a deep sea is shrunken or expanded by a temperature deviation over 100 degrees, and physical changes such as a length change occur due to a pressure change in the pipeline.
Accordingly, in the pipeline installed at the sea, stresses are intensively generated at a plurality of specific or unspecified points, which results in buckling or deformation. In addition, in a touch down zone where a pipeline installed at the seabed is connected to a riser serving as a marine carrier, the pipeline may pitch and roll due to a plurality of external environmental forces such as sea current, wave, tidal current, wind, temperature or the like.
In order to measure such pitch and roll, various kinds of monitoring methods are being used at the present. In an existing monitoring method, a deformation rate of the pipeline is measured by using an electric-type or optical fiber-type deformation sensor. In a marine structure, a welding portion is most vulnerable in a structural aspect, and thus sensors are installed and operated at intervals of 20 to 50 cm. Here, sensors are installed in a length direction of the pipeline to analyze deformation. In another monitoring method, an electric-type inclinometer is used to detect deformation of the pipeline.
However, such existing monitoring methods have difficulty in accurately analyzing situations since a deformation rate caused by temperature or pressure of a marine structure is much greater than a deformation rate caused by buckling or walking. In addition, an electric-type inclinometer currently used is installed in the sea and thus has problems such as loss by water leak caused by high hydraulic pressure and complexity in its power supply device and connection method, and thus a new measurement method allowing easier use is demanded. In addition, sensors used in the existing monitoring methods have short fatigue measurement durability life, and thus sensors useable for a longer time are needed.
During operation of a marine structure, fluid flow inevitably applies an internal or external force to the marine structure. Particularly, in case of a fixed marine structure mooring at a specific point on the sea, it is essential to control so that the internal or external force caused by such fluid flow is minimized.
In addition, during operation of a marine structure, aerodynamic and hydrodynamic environmental internal or external force and hull stresses may cause turnover of a ship or fall of cargos, and this problem should be solved urgently.
Meanwhile, it is an essence in the future marine shipbuilding industry to develop and build a marine structure having low fuel consumption. Assuming that marine structures consume 100 tons of fuel and exhaust 320 tons of carbon dioxide, if the fuel efficiency is improved by 1%, costs may be reduced over 240,000 dollars per year, about 6 million dollars for 24 years. In the used ship market, the fuel efficiency is one of the most important factors.
In addition, the modern society mostly depends on motorized transportation systems which exhaust greenhouse gas, but it is widely known that exhaustion of CO2 is a main cause of global warming, climate change and ocean acidification. In view of the amount of CO2 exhausted for transporting 1 ton of cargo by 1 mile, a marine structure is most efficient among all kinds of transportation means. However, since marine structures are overwhelming transportation means in the world trade, the amount of exhausted CO2 by marine structures occupies about 3% in the entire greenhouse gas exhaustion. Therefore, if the fuel efficiency of marine structures is enhanced, the amount of exhausted greenhouse gas in the industry may be greatly reduced.
In addition, existing manual or semi-automated marine make a large difference in their operations due to the skill level of workers, and a system developed to use a semi-automation mode may be applied just to a corresponding marine structure. Therefore, in order to implement a system inclusively applied to various kinds of ships, a software engineering approach is required, and a software framework for providing a basis for developing similar kinds of applications should be developed.